Suggest Treatment For Severe Itchiness In The Vagina

My vagina has been extremely itchy for the past few days. Also, my urine has smelled funny for almost a month now. I had sex with my boyfriend 4 days ago and 30 minutes afterwards, my vagina became swollen, itchy, and sore. I put ice on it that night and the swelling went down a little bit. But since then, my vagina has been severely itchy. When I urinated, it burned and still smelled bad. What was the cause? What is it? What should I do?